DMARC has three policies: p=none (monitor), p=quarantine (route to spam), and p=reject (refuse entirely). This guide covers the roll-out roadmap, how long to ...
A single domain sending from Mailgun, Mailchimp, Workspace and other ESPs needs a separate DKIM selector for each sender. This guide covers the selector ...
ARC (Authenticated Received Chain, RFC 8617) lets mailing lists, forwarders and gateways preserve authentication results when they modify messages in ways that ...
BIMI displays your brand logo next to authenticated emails in Gmail, Yahoo, Apple Mail and other providers. This guide covers what BIMI does (and doesn't do), ...
Your emails are going to spam for one of 12 reasons: authentication, reputation, complaints, list hygiene, sending patterns, content, unsubscribe, engagement, ...
GlockApps, MailReach, Mail Tester and Email on Acid each test inbox placement differently. This guide compares methodology, provider coverage, and use case, ...
Outlook Focused Inbox splits mail into Focused (priority) and Other (everything else). This guide covers how the classifier works, the signals that push mail ...
Gmail sorts inbound mail into 5 tabs: Primary, Promotions, Social, Updates, and Forums. This guide explains how the classifier works, the signals that push ...
Inbox placement rate measures what share of your accepted mail actually lands in the primary inbox, not spam, promotions, or quarantine. This guide covers the ...
Code551 5.1.1 Bounce typeHard bounce RetryableNo Action neededRemove address from list Typical error message 551 5.1.1 recipient is not exist. Hard bounce, the ...
